This invention relates to a sheet material cutting method and apparatus wherein sheet material is taken from a supply and advanced along its length to a cutting station, and is cut across its length. More particularly, the invention relates to a system for cutting terry cloth towel and similar sheet material having bands extending across its length of different character than the remaining sheet material, such bands being of different thickness, different color or other texture. The process includes the steps of feeding the sheet material toward a cutting station, detecting the bands as they approach the cutting station at opposite side portions of the sheet material and stopping the movement of each side of the sheet material independently of the other side so that each side portion of the sheet material is precisely postioned at the cutting station. The sheet material is then stretched across the cutting station so as to assure that the filler threads of the sheet material are properly oriented at the cutting station, and a cut is made through the sheet material while the sheet material is stretched.
In the manufacture of terry cloth towels and other flat goods, it has been difficult to accurately cut the goods from a continuous supply into short lengths with the cuts being formed at the proper location in the goods. For example, a popular design for terry cloth towels is to have the main body of the terry cloth towel include a plush surface of terry cloth, and then at the ends of the towel to have several bands of lesser thickness and of different lengths adjacent a hem or fringe. The terry cloth towel material is woven in a very long length, and the supply of the terry cloth towel material must be cut across its length to form the individual towels, etc.
The terry cloth towel material has been cut by hand, by a worker moving the towel material along a work surface, locating the thin bands of the towel material, and then moving a motorized cutting implement with a rotatable disc and cutting with the disc through the thin bands of the towel material to cut the material. This is a slow operation, requires a skilled worker, and occasionally results in an improper cut being made.
Another prior art apparatus for cutting terry cloth towel and the like with thin bands extending across the material into lengths of toweling includes an automated cutter wherein the supply of towel material is fed toward a cutting station between a pair of parallel rotatable rollers that are spaced apart a distance that prevents the rotation of the rollers from moving the thin portions of the material. When a thin band on the towel material is detected, the rollers are operated to run in the reverse direction and the rollers move the thick part of the material backwards along the feed path until the thin portion of the material is located between the feed rollers. This locates the thin portion of the material at the cutting station and a cut is made across the material a predetermined distance from the rollers. While this type of equipment functions to make a cut through the towel material at the thin bands of the material, the equipment operates at a relatively slow speed, and the equipment does not work well on relatively thin terry cloth material. Moreover, some terry cloth material is likely to have a pattern of thin bands extending across the material so that the towel cut from the material has a design at its opposite ends of alternating long and short bands of thin material. It is difficult for the prior art automatic cutting equipment to distinguish between the long and short thin bands so as to make the cut in the long thin band and not in a short thin band. Also, the prior art cutting equipment cannot determine the difference between a properly formed thin band extending across the sheet material and a flaw extending across the sheet material.
Another prior art towel cutting device comprises a detecting system for locating bands formed in the terry cloth material that include no filler threads, so that when a cut is made through these thin bands a towel with a loose fringe is formed. The detection equipment includes a feeler that tends to fall through the areas of the towel material that have no filler threads so as to locate the proper portion of the towel material to make the cut. The detector tends to accumulate thread, lint and debris and to become inoperable after the system has been operated for some period of time. Also, the detection system has not proven to be 100% reliable in that slack in one edge portion of the towel material caused by non-uniform weaving of the material tends to cause an incorrect cut across the material.
In general, when the supply of towel material is fed to a cutting station, the material must have the proper thin band, usually the longest of the thin bands, positioned at the cutting station before the cut can be made. One edge portion of the towel material might be fed slightly ahead of the opposite edge portion, and it is desirable for the equipment to adjust the edge portions of the material at the cutting station so that the ends of the filer threads are parallel to the path of the cutting equipment, or the cutting equipment will make a cut that is not parallel to the filler threads of the material. Moreover, even if the opposite edge portions of the supply of towel material are properly aligned with respect to each other at a cutting station, it is likely that there will be some sag in the filler threads at the center portion of the towel material, where the filler threads are curved forwardly or rearwardly along the length of the material from the opposite edges of the material. If a straight cut is made across the material while the sag has not been removed from the filler threads, several of the filler threads will be cut intermediate their ends. This results in an improperly formed product. Therefore, it is desirable to stretch the material across its length at the cutting station to straighten the filler threads as the cut is made.